High-frequency signaling system



Dec. 18 1923. 1,477,899

c. w. RICE HIGH FREQUENCY SIGNALING SYSTEM Filed July 2'7. 1921 ChestrWRice, *2! M14.

His Attorne g.

Patented Dec. 18, 1923.

UNITED STATES PATENT OFFICE.

CHESTER W. RICE, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRICCOMPANY, A CORPORATION OF NEW YORK.

HIGH-FREQUEN CY SIGNALING SYSTEM.

Application filed July 27, 1921.

To all whom it may concern:

Be it known that I, CHESTER W. RICE, a citizen of the United States,residing at Schenectady, in the county of Schenectady, State of NewYork, have invented certain new and useful Improvements inHigh-Frequency Signaling Systems, of which the following is aspecification.

My present invention relates to high frequency signaling systems, andmore particularly to'systems for receiving high frequency radio signals.

The object of my invention is to provide an improved system for thereception of high frequency radio signals whereby the stray or staticratio may be materially im proved.

In carrying my invention into effect I provide at the receiving stationa means for storing up the energy ofthe received high frequency impulsesfor a plurality of successive cycles of the high frequency current andmeans for impressing simultaneously upon the receiving apparatus aplurality of currents produced by energies received at different timeperiods. The energy storing means may be in the form of an artificialtransmission line which prefer ably has an effective length equal to aplurality of wave lengths of the signals to be received. The signals tobe received are impressed upon this transmission line and currents inthe transmission line from a plurality of selected points along itslength are impressed upon receiving apparatus in such a way that thesecurrents will add amplitudes in the receiving apparatus. The amplitudeof the current impressed upon the receiving apparatus will consequentlybe equal to the arithmetical sum of the amplitudes of the respectivecurrents or the product of the number of separate currents and themaximum amplitude of one, all these currents being substantiallyproportional to the amplitude of the signaling cur rent in thetransmission line. Stray currents of short duration which may beimpressed upon the transmission line will however be of difierentamplitude at the different points in the transmission line from whichcurrents are selected, and in case by :hance these stray currents addamplitudes in the receiving apparatus their sum will Serial No. 487,998.

not be equal to the product of the number of stray currents by themaximum amplitude, but will be of a value somewhat smaller than suchproduct. Stray currents having a different frequency than the signalingcurrent will have different phase relations along the transmission linefrom the signaling currents, and as a result such currents will not addamplitudes in the receiving apparatus, but will merely add energies. Asa result the stray ratio may be considerably improved.

The novel features which I believe to be characteristic of my inventionare set forth in the appended claims, my invention itself, however, bothas to its organization and method of operation will best be understoodby reference to the following description taken in connection with theaccompanying drawing in which I have indicated diagrammatically one wayin which my invention may be carried into effect.

As indicated in the drawing, currents received upon a receiving antenna1 are impressed by means of the usual coupling transformer 2 upon anartificial transmission line 3, which preferably has an effective lengthat least equal to several wave lengths of the signaling currents to bereceived. By means of the couplings 4 located at different points alongthe transmision line, signaling currents may be impressed upon the inputcircuits of an equal number of vacuum tube amplifiers 5. The outputcircuits of these amplifiers are connected in parallel and supplied withenergy by the common source 6, these output circuits may or may notinclude areasonant circuit which is tuned for the signaling frequency.The signaling currents set up in the output circuits may be impressed bymeans of the coupling 8, upon the input circuit of a detector 9, or ifdesired, other amplifiers may be interposed between the output circuitsof amplifiers 5 and the detectors. The end of the transmimion linedistant from the receiving antenna is preferably shunted by a resistance11 equal to the surge in!- pedance of the transmission line in order toprevent any reflection of the currents transmittedover the line.

In the ircuit arrangement illustrated it is assume that the couplingcoils 4 are 16* cated a wave length or a multiple of a wave length apartalong the transmission line. By this arrangement the signaling currentimpressed upon the transmission line will cause the potential of thegrids 10 of the different amplifiers to vary in phase. correspondingcurrent variations produced in the output circuits of the amplifierswill therefore be in phase and will add amplitudes. a

Each dot or dash of the telegraphic signal being ordinarily made upof alarge number of cyclesof the high frequency current the signalingcurrents thus impressed upon the signaling apparatus willafter the firstfew cycles of the signal all be of substantially equal amplitude. Theamplitude of the current produced in the combined output circuitstherefore will be equal totthe arithmetical sum of the amplitudes of theseparate currents, or the product of the current in one amplifiermultiplied by the number of amplifiers employed. 'Stray'impulses on theother hand of short duration or high decrement will ordinarily be of themaximum am litude at any instant at only one or two 0 the points atwhich the signaling currents are selected. In case such impulses are ofthe same frequency as the signaling currents so that they will addamplitudes in the receiving apparatus, the total amplitude of suchcurrents in the receiving apparatus will be of a value materially lessthan the product of the maximum amplitude by the number of amplifiersemployed.

For stray currents which are not of the same frequency as the signalingcurrent, the currents produced in the output circuits of the amplifierswill not be in phase, and as a result the energies of these currentsonly will be added in the output circuits and not their amplitudes. As aresult the stray ratio with respect to such impulses will also bematerially improved.

While in the system illustrated and described all the signaling currentsare assumed to be selected from points along the line which are a wavelength or a multiple of a wave length apart, it will be apparent thatsimilar results may be obtained by selecting points a half wave lengthor a multiple of a half wave length apart, and by impressing thecurrents from the output circuits of the different amplifiers upon thereceivin apparatus in such a way that they will all e in phase and willtherefore add am litudes.

at I claim as new and desire to secure by Letters Patent of the UnitedStates, is: 1. The combination in a high frequency signal receiving.system of an artificial transmission line having an effectivelengthequal to a lurality of wavelengths of the signals to e received,means for impressing the signaling currents to be received The I uponsaid transmission line, receiving apparatus and means for impressingupon said receiving apparatus signaling currents derived from more thantwo points in said transmission line. 1

2. Means for improving the stray ratio in a high frequency signalreceiving system comprising an artificial transmission line having aneffective length equal to a plurality of wave lengths of the signals tobe received, means for impressin signaling currents to be received uponsaid transmission line, receiving apparatus and means for impressingupon said receiving apparatus signaling currents derived from more thantwo points in said transmission line so chosen that the signalingcurrents will add amplitudes in the receiving apparatus whileinterfering currents of different frequency Will add energies only.

3. The combination .in a high frequency signal receiving system of anartificial transmission line having an effective length equal to aplurality of wave lengths of the signals to be received, means forimpressing the signaling currents to be received uponsaid transmissionline, receiving apparatus and means for impressing upon said receivingapparatus signaling currents derived from a plurality of points in saidtransmission line, said points being a wave length or a multiple of aWave length apart.

4. The combination in a high frequency signal receiving system of anartificial transmission line having an effective length equal to aplurality of wavelengths of the signals to be received, means forimpressing the signaling currents to be received upon said transmissionline, receiving apparatus and means for impressing upon said receivingapparatus signaling currents derived from more than two points in saidtransmission line, said ints being so chosen and the different signalingcurrents impressed upon the receiving apparatus in such a way that thesignaling currents will add amplitudes in the receiving apparatus.

5. The combination in a high frequency signal receiving system of anartificial transmission line having an effective length 1 equal to aplurality of Wave lengths of the signals to be received, means forimpressing the signaling currents to be received upon one end of saidtransmission line, the other end of said transmission line beingprovided with means for preventing reflection, receiving apparatus, andmeans for impressing upon said receivingapparatus signaling currentsderivedfrom more than two points in said transmission line.

6. The combination in a high frequency signal receiving system of anartificial transmission line having an effective length equal to aplurality of wave lengths of the signals to be received, means. forimpressing the signaling currents to be received upon one end of saidtransmission line,

surge impedance, receiving apparatus, and

means for impressing upon said receiving apparatus signaling currentsderived from more than two points in said transmission line.

7. The combination in a high frequency signal receiving system of anartificial transmission line having an effective length equal to aplurality of wave lengths of the signals to be received, means forimpressing the signaling currents... to be received upon saidtransmission line, receiving apparatus and more than two vacuum tubeamplifiers having their input circuits coupled to a plurality of pointsin said transmission line, and their output circuits connected to thereceiving apparatus.

8. The combination in a high frequency signal receiving system of anartificial transmission line having aneflective length equal to aplurality of Wave lengths of the signals to be received, means forimpressing the signaling currents to be received upon said transmissionline, receiving apparatus and a plurality of vacuum tube amplifiershaving their input circuits ,coupled to a plurality of points. in saidtransmission line which are a wave length or a multiple of a wave lengthapart, and their output circuits connected to the receiving apparatus.

9. The combination in a high frequency signal receiving system of anartificial transmission line having an efiective length equal to aplurality of wave lengths of the signals to be received, means forimpressing the'signaling currents to be received upon said transmissionline, receiving apparatus and more than two vacuum tube amplifiershaving their input circuits coupled toa plurality of points in saidtransmission line, and their output circuits connected to the receivingapparatus, said points being so chosen and the output circuits of theamplifiers being so connected to the receiving apparatus that thesignaling currents will add amplitudes in the receiving apparatus.

10. The combination in a high frequency signal receiving system of anartificial transmission line having an effective length equal to aplurality of wave lengths of the signals to be received, means forimpressing the signaling currents to be received upon said transmissionline, receiving apparatus and more than two vacuum tube amplifiershaving their input circuits coupled to a plurality of points in saidtransmission line and their output circuits connected to the receivingapparatus said points being so chosen and the output circuits of theamplifiers being so connected to the receiving apparatus that thesignaling currents will add amplitudes in the receiving apparatus whileinterfering currents of different frequency will add energies only.

11. The combination in a high fl'C(lll(Ht' signal receiving system of anartificial transmission line having an effective length equal to aplurality of wave lengths of the signals to be received, means forimpressing the signaling currents to be received upon one end of saidtransmission line, the other end of said transmission line being shuntedby a resistance equal to its surge impedance, receiving apparatus, andmore than two vacuum tube amplifiers having their input circuits coupledto a plurality of points in said transmission line and their outputcircuits connnected to the receiving apparatus, said points being sochosen and the output circuits of the amplifiers being so connected tothe receiving apparatus that the signaling currents will add amplitudesin the receiving apparatus, while interfering currents of differentfrequency will add energies only.

12. The combination in a high frequency signal receiving system of meansfor storing up the energy of received high frequency electricalimpulses, receiving apparatus and means for impressing upon thereceiving apparatus simultaneously more than two currents produced bythe energies of signalingdimpulses received at difierent time pe r10 s.

13. The combination in a radio receiving system of a receiving antenna,means for storing up the energy of high frequency electrical impulsesreceived upon said antenna, receiving apparatus and means for impressingupon the receiving apparatus simultaneously more than two currentsproduced by the energies of signaling impulses received at differenttime periods.

14. The combination in a high frequency signal receiving system of meansfor storing up the energy of received high frequency electricalimpulses, receiving apparatus and means for impressing upon thereceiving apparatus more than two substantially in phase currentsproduced by the energies of desired signaling impulses received atdifferent time periods.

15. The method of receiving high frequency signals which consists instoring up the energy of received high frequency impulses representingsignals and impressing upon a receiving apparatus more than two currentsproduced by the energies of signaling impulses received at differenttime periods.

16. The method of receiving high frequency signals which consists instoring up the energy of high frequency electrical impulses representingsignals and impressing upon a receiving apparatus more than twosubstantially in phase currents produced by the energies of desired,signaling impulses received at different time periods.

17 The method of improving the stray ratio in a radio receiving systemwhich consists in storing up the energy of received high frequencyimpulses and impressing up a receiving apparatus more than two currentsproduced by' energies received at different time periods in such a waythat currents reduced by desired signaling im- 10 pulses wi 1 addamplitudes in the receiving apparatus While currents produced byinterfering impulses will merely add energies.

In witness whereof, I have hereunto set my hand this 26th day of July,1921.

CHESTER W. RICE.

